package com.example.hzk.myapplication;

import android.graphics.Camera;
import android.graphics.Matrix;
import android.view.animation.Animation;
import android.view.animation.Transformation;

/**
 * 围绕y轴旋转并沿着z轴平移实现一种类似于3D的效果
 * Created by hzk on 2019/6/20.
 */
/**
 * Creates a new 3D rotation on the Y axis. The rotation is defined by its
 * start angle and its end angle. Both angles are in degrees. The rotation
 * is performed around a center point on the 2D space, definied by a pair
 * of X and Y coordinates, called centerX and centerY. When the animation
 * starts, a translation on the Z axis (depth) is performed. The length
 * of the translation can be specified, as well as whether the translation
 * should be reversed in time.
 *
 *  fromDegrees the start angle of the 3D rotation
 *  toDegrees the end angle of the 3D rotation
 *  centerX the X center of the 3D rotation
 *  centerY the Y center of the 3D rotation
 *  reverse true if the translation should be reversed, false otherwise
 */
public class Rotate3dAnimation extends Animation {
    private final float mFromDegrees;
    private final float mToDegrees;
    private final float mCenterX;
    private final float mCenterY;
    private final float mDepthZ;
    private final boolean mReverse;
    private Camera mCamera;
    public Rotate3dAnimation(float fromDegrees, float toDegrees,
                             float centerX, float centerY, float depthZ, boolean reverse) {
        mFromDegrees = fromDegrees;
        mToDegrees = toDegrees;
        mCenterX = centerX;
        mCenterY = centerY;
        mDepthZ = depthZ;
        mReverse = reverse;
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
        mCamera = new Camera();
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        final float fromDegrees = mFromDegrees;
        float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);
        final float centerX = mCenterX;
        final float centerY = mCenterY;
        final Camera camera = mCamera;
        final Matrix matrix = t.getMatrix();
        camera.save();
        if (mReverse) {
            camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
        } else {
            camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
        }
        camera.rotateY(degrees);
        camera.getMatrix(matrix);
        camera.restore();
        matrix.preTranslate(-centerX, -centerY);
        matrix.postTranslate(centerX, centerY);
    }
}
